[8u-dev] Request for approval: Backport of 8011858

[Vladimir Kozlov]

On 9/15/15 6:54 AM, Zoltán Majó wrote:
> Hi Vladimir,
>
>
> thank you for the feedback!
>
> On 09/14/2015 06:00 PM, Vladimir Kozlov wrote:
>> On 9/14/15 7:31 AM, Zoltán Majó wrote:
>>> Hi,
>>>
>>>
>>> I would like to request the backport of the fix for JDK-8011858 to 8u-dev. The fix can help reducing the memory usage of
>>> the C2 compiler and is therefore needed to fix JDK-8129847.
>>>
>>> Original (9) bug: https://bugs.openjdk.java.net/browse/JDK-8011858
>>> Original changeset: http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/af60f1cb36f2
>>>
>>> Unfortunately, the fix does not apply cleanly, as two affected files are different in 9 and in 8u-dev. Here are the
>>> changes that I did not (could not) apply to the 8u-dev tree:
>>
>> Can you scan jdk8u C2 code for other cases where C->unique() is used for stack. May be some were removed in jdk9. But
>> we still need to fix them.
>
> I found two places where we can use live_nodes() instead of unique():
> 1) in matcher.cpp on line 345 for determining the stack size used in xform();
> 2) in compile.cpp on line 330 for the estimated worklist size.
>
> I updated these source code locations accordingly.

Nice!

>
> These changes could be applied to 9 as well. Do we want to do that? If yes, I guess a good way to do it would be to file
> a separate bug/enhancment for 9. Or do you see some other way?

Yes, file separate rfe. No other way. And check again - may be we missed more in jdk9.

>>
>>> - http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/af60f1cb36f2#l6.8
>>> - http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/af60f1cb36f2#l9.8
>>
>> node.cpp has next code in dump_nodes() which you should fix (I look on jdk8u/jdk8u/hotspot code):
>
> Thanks for catching that. I changed that code as well.
>
> Here is the newest webrev:
> http://cr.openjdk.java.net/~zmajo/8011858_8u/webrev.01/

Looks good.

Thanks,
Vladimir

>
> All JPRT tests and all JTREG compiler tests (that pass with an unmodified VM) pass.
>
> Thank you and best regards,
>
>
> Zoltan
>
>>
>> GrowableArray <Node *> nstack(C->unique());
>>
>> Thanks,
>> Vladimir
>>
>>>
>>> Webrev: http://cr.openjdk.java.net/~zmajo/8011858_8u/webrev.00/
>>>
>>> Testing:
>>> - the fix was pushed into 9 on Aug 11 and did not cause any nightly failures;
>>> - all JPRT tests pass;
>>> - all JTREG tests pass that pass with the unmodified VM.
>>>
>>> Thank you and best regards,
>>>
>>>
>>> Zoltan
>>>
>